Two houses on Rectory Road were cordoned off by police
Five houses are being searched in Burnley after nine men were arrested by counter-terrorism police.
The nine were arrested when several vehicles were stopped on the M65 near Preston on Friday night, but six were later released without charge.
The arrests were made in a joint operation between Lancashire Police and the North West Counter Terrorism Unit.
Police have confirmed the vehicles were meant to be part of the Gaza aid convoy which left London earlier.
More than 100 vehicles are taking more than £1m worth of aid, including trucks full of medicines, tools, clothes, blankets and shoe boxes as well as gifts for children.
The mission is organised by umbrella body Viva Palestina and backed by Muslim groups.
Lancashire Police said officers were in the Burnley area where the searches were being carried out and residents living nearby would be kept informed.
The houses being searched are understood to be on Gordon Street, Robinson Street and Clive Street, and two are on Rectory Road.
Nine men were arrested by counter-terrorism police on Friday
Two adjacent end-of-terrace houses on Rectory Road and the vehicles parked outside them were cordoned off with police tape as officers patrolled the street on Saturday.
A white Nissan Micra nearby was also surrounded by police tape.
Ch Supt Neil Smith, Divisional Commander for Pennine Division, said: "This is a very sensitive time for all our communities and we are working hard to ensure everyone is kept up to date with as much information as we can give.
"We will endeavour to carry out any searches as quickly as possible to minimise impact on the area concerned. However, inquiries of this nature are complex and may take time to resolve.
"I would like to thank local residents affected by these searches for their cooperation and ask that they remain patient. We will ensure people are kept updated in relation to the investigation as and when we can."
Three men aged 26, 29 and 36 are still being questioned by police following Friday's arrests.
The men were stopped as they travelled westbound on the M65 near junction one at about 2100 GMT.
It is understood the operation is connected to possible terrorist offences overseas and not in the UK.
The motorway was closed while several vehicles they were travelling in were seized.
The houses in Burnley where anti-terror police are working
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